Weatherstrip products made by dual extrusion or coextrusion of cellular and non-cellular plastic resins are well-known in the art. Examples of such products are shown in U.S. Pat. No. 3,535,824 and U.S. Pat. No. 3,685,206 to Kessler. The Kessler patents disclose a dual extruded weatherstrip product having a rigid base with a flexible strip that is mechanically interlocked and thermally fused to the base.
The Kessler patents teach that the products are made by xe2x80x9cwell-known dual extrusion processes,xe2x80x9d which would include the standard processing techniques shown in, for example, Boutillier U.S. Pat. No. 3,879,505 or in Hoffman U.S. Pat. No. 4,690,862. Such standard processing techniques, are described in both Boutillier and Hoffman, as well as in numerous other references, and have been used to produce products that have been available commercially since at least the early 1980""s (e.g., the Victorian Molding product made by Gossen Corporation). These processes involve the extrusion of cellular and non-cellular resins through separate extruders into a common die. The resins meet either inside or immediately upon exiting the die and then travel through a sizing box and cooling tank, which are typically under vacuum pressure conditions in order to maintain the size of the cellular plastic portion as the profile is cooled.
Both Kessler and Hoffman teach the use of a bulbous tongue to form a mechanical interlock between the two plastics, which is in addition to the thermal or chemical fusion that occurs between the plastics during the extrusion process. Hoffman, in particular, teaches that the bulbous tongue is important to maintain the tongue portion within the corresponding groove portion of the mating profile during the extrusion process and during use of the product. The assignee of the Hoffman patent, Gossen Corporation, has commercially sold weatherstrip product both with and without the bulbous tongue shown in the Hoffman patent.
The present invention provides a weatherstrip product for use in garage doors and similar applications in which the flexible portion is subjected to back and forth movements by the opening and closing of the garage door and therefore needs to be securely held by the mating portion. The present invention provides such a weatherstrip product, but avoids the use of the bulbous tongue configuration that is taught to be so important in the Hoffman patent.
Other prior art garage door weatherstrip products have been provided which eliminate the bulbous tongue, and thus any encapsulation of the tongue within the mating groove. These prior art products (e.g., the Thermo*Stop made by Marley Mouldings, the assignee of the present invention), use thermal fusion (but no mechanical interlock) to hold a flexible, non-cellular piece within a V-shaped groove in a cellular portion. While these prior art products provide a satisfactory garage door weatherstrip without the need for the bulbous tongue (and thus the encapsulation) taught in Hoffman, the present invention, in its preferred embodiment, avoids the formation of any groove in the cellular base for mating with the non-cellular strip. While other prior art weatherstrip products have utilized a non-cellular piece fixedly abutted against a cellular piece, or a non-cellular flap extruded along the surface of a cellular piece, one embodiment of the present invention provides an extended surface area of contact that allows use of the weatherstrip as a garage door weatherstrip product in which the flexible portion is repeatedly contacted or moved by the garage door or other external forces. An example of a prior art weather seal for a garage door with a solid base and a pivoting seal member is shown in U.S. Pat. No. 5,092,079. An example of a prior art weatherstrip with a cellular (foamed) portion and a solid, or non-cellular portion is shown in UK Patent Application GB 2,183,707.
An example of a prior art sequential extrusion process is shown in Guy U.S. Pat. No. 4,600,461. In that patent, a non-cellular piece is extruded onto the top of a cellular base before both portions are drawn through a sizing or cooling chamber. Another example of a prior art sequential extrusion process for extrusion forming of a thermoplastic, double-walled, foam-core conduit is shown in U.S. Pat. No. 4,322,260.
An extrusion product or profile is formed by extrusion of a cellular compound to form a base and then subsequent extrusion of a non-cellular compound to form an attached flexible strip. The final product or profile is used as a garage door weatherstrip in which the cellular base is mounted against the door jamb and the strip of flexible non-cellular material extends out from the cellular base to prevent the flow of air through openings between doors and adjacent jambs or frames.
The present invention also includes the process for forming such a product. The process involves sequential extrusion of the two portions of the product. First, a cellular base is extruded through a die and vacuum sizer and allowed to cool. Next, a saddle die is used to apply the flexible non-cellular strip to a portion of the cellular base. Preferably, the saddle die heats a portion of the cellular base to improve the bond between the cellular and non-cellular portions.